In recent years, there has been an increase in the importance of disposal technology for disposing of waste matter generated during the operation of a nuclear power generation facility, or waste matter generated as the result of decommissioning a reactor. In order to reduce the cost incurred in, for example, the control, stocking, or controlled disposal of a spent ion-exchange resin (hereafter called a “processing target resin”) used in a nuclear power generation facility, processing target resin volume reduction process technology has been developed. To date, a volume reduction process has been carried out on the processing target resin using a method whereby, for example, a radioactive nuclide is separated from the processing target resin, and the processing target resin is burned together with combustible waste matter, or the like. However, a processing target resin for which burning is not appropriate has been temporarily stored by, for example, stocking on the premises of a nuclear power generation facility. A volume reduction processing device utilizing oxygen plasma is disclosed in, for example, Patent Document 1 (JP-A-2001-153998) as a method for reducing the volume of this kind of processing target resin.
A high volume reduction ratio is achieved with the volume reduction processing device disclosed in Patent Document 1. That is, with a processing using the volume reduction processing device disclosed in Patent Document 1, the volume of the processing target resin is reduced at a high volume reduction ratio by combining a process breaking down or carbonizing the processing target resin with heat and a process oxidizing or ashing gas generated by the breakdown or the carbonized processing target resin, using oxygen plasma. To give a numerical example confirmed by the inventor of the application, with the method disclosed in Patent Document 1, when measuring a mass when moisture is removed from the processing target resin by dripping (a drained standard mass), and contrasting it with the mass of a solid matter forming a residue after volume reduction (hereafter called a “residual solid matter”), it is possible to reduce the volume of the processing target resin to in the region of, for example, one-twentieth. As a result of this, even when fabricating a mortar-like solidified waste by sealing the residual solid matter by mixing it with, for example, cement, there is no noticeable decrease in the strength of the solidified waste, which is also true of mortar including a fine aggregate such as sand. Because of this, there is an advantage in that it is possible to load a greater amount of the residual solid matter within the range of a strength standard provided for the solidified waste, that is, a solidified waste standard strength condition, which leads to a reduction in disposal expenses. Moreover, when employing the method disclosed in Patent Document 1, it is possible to carry out volume reduction with the radioactive nuclide allowed to remain in the residual solid matter.